This is a collection of brief (3 to 4-page) essays in various topics in mathematics, written for a general audience. The essays are arranged in alphabetical order by subject, but otherwise there is no particular organization or pattern to the book. The essays are lightly cross-referenced, and there is a good index. There are also corny jokes that appear unexpectedly in the middle of serious expositions. The book is not closely related to the author’s earlier similarly-titled book Innumeracy.

The book is slanted toward modern mathematics, and shows a good balance between keeping the exposition simple enough for a general reader and showing some useful mathematics. A lot of the topics will already be familiar to readers of popular math books, for example the bridges of Königsberg and Gödel’s theorem, but many are interesting and less-familiar. There is a modest amount of computer science included, dealing with artificial intelligence and complexity of computation.

My favorite topics in the book are coincidences, the French literary movement Oulipo, and the smidgen of Ramsey theory (in a group of six people, either there are three, all of whom know each other, or three, none of whom know each other).

Bottom line: an interesting, unusual, and only slightly-dated popular sampler of mathematics.